Seri adjective 1noun 1forms 3 adjective1 •Of the Seris or their language.It is believed that the Céres Indians have discovered a method of poisoning their arrows. — 1829 noun1 •A member of an indigenous group of Sonora, Mexico.The Céres, like the Malay pirates of India, neither gave nor received quarter. — 1829 formsSeris · more Seri · most Seri